Hong Kong -LRB- CNN -RRB- -- Brothers Thomas and Raymond Kwok , who control Hong Kong 's biggest property development company , Sun Hung Kai , have been arrested for suspected corruption , authorities said Thursday .

Also arrested for suspected corruption was a person described by Hong Kong 's Department of Justice as `` a former principal official of the government of the Hong Kong Special Administrative Region , '' a spokesman for the Independent Commission Against Corruption said .

The Kwok brothers ' fortune is $ 18.3 billion , according to Forbes Magazine , which rank the brothers and their family as the 27th richest in the world .

The commission 's report said `` the arrested persons are alleged to have committed offenses under the Prevention of Bribery Ordinance and misconduct in public office . ''

The arrests come 10 days after Sun Hung Kai 's executive director , Thomas Chan , was arrested by the commission in connection with a bribery investigation .

Four other people , whose backgrounds were n't disclosed by authorities , were also arrested on corruption charges .

On Thursday morning , Sun Hung Kai Properties suspended trading of its shares . The company has since announced the shares will resume trading when Hong Kong 's stock exchange opens Friday morning .

The firm has set up a special committee to handle all matters arising from the investigation , and the company 's board , whose six members include the two brothers , has resolved that the Kwoks will `` continue to undertake and discharge their duties to the group , including their duties as joint chairmen and managing directors of the company , '' according to a company statement .

CNN 's Andrew Henstock contributed from Hong Kong and Michael Martinez from Los Angeles .

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Thomas and Raymond Kwok run Hong Kong 's biggest property development company

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They were arrested for suspected corruption

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An unidentified government official was also arrested for alleged corruption

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Another Sun Hung Kai executive was arrested 10 days ago in a bribery investigation